The formation and cleavage of the O-O bond is a crucial reaction for aerobic organisms. Reductive O-O breakage takes place in aerobic organisms in cytochrome C oxidase,1 where it constitutes the basic constituent of cellular respiration, and represents a primary source of energy. O-O cleavage also takes place in oxygenases,2 and results in the generation of highly electrophilic high valent metal-oxo species, responsible for oxidative transformations. On the other hand, O-O bond formation takes place at a Mn4Ca cluster in the Oxygen Evolving Center of Photosystem II (PSII) of green plans and some bacteria. In both oxidative and respiration enzymes, metal ions adopting high oxidation states result from reductive O-O cleavage reactions while in PSII they are responsible for O-O bond formation.3 Selected iron coordination complexes have been shown to catalyze analogous reactions, entailing controlled cleavage of the O-O bond, and water oxidation. Control over the former reaction enables the design of iron oxidation catalysts as appealing tools for organic synthesis.4 Elucidating the factors that govern the latter is interesting because this reaction is considered one of the most difficult steps for developing artificial photosynthesis. In this contribution the implication of high valent iron-oxo species as competent intermediates in reactions involving O-O lysis and formation are discussed.5-6 1) S. Ferguson-Miller, G. T. Babcock, Chem. Rev. 1996, 96, 2889-2907. 2) a) M. Costas, M. P. Mehn, M. P. Jensen, L. Que, Jr., Chem. Rev. 2004, 104, 939-986. B) B. J. Wallar, J. D. Lipscomb, Chem. Rev. 1996, 96, 2625-2658. C) E. I. Solomon, et al. Angew. Chem. Int. Ed. 2001, 40, 4570. d) S. Shaik, et al. Chem. Rev. 2010, 110, 949-1017. e) E. G. Kovaleva, J. D. Lipscomb, Nat. Chem. Biol. 2008, 4, 186-193. 3) Y. Umena, K. Kawakami, J.-R. Shen, N. Kamiya, Nature 2011, 55. 4) a) Oloo, W. N.; Que, L. Acc. Chem. Res. 2015, 48, 2612. b) Bryliakov, K. P.; Talsi, E. P. Coord. Chem. Rev. 2014, 276, 73. c) A. Company, et al. in Iron-Containing Enzymes, Versatile Catalysts of Hydroxylation Reactions in Nature, RSC, Cambridge, 2011. 5) a) O. Cusso et al. J. Am. Chem. Soc. 2013, 135, 14871 b) O.Cussó et al. Angew. Chem. Int. Ed. 2015, 54, 2729. c) Cusso, O.; Ribas, X.; Costas, M. Chem. Commun. 2015, 51, 14285. [6] a) J. Lloret-Fillol Nat. Chem. 2011, 3, 897, b) Codola, Z.; Gomez, L.; Kleespies, S. T.; Que, L., Jr.; Costas, M.; Lloret-Fillol, J. Nat. Commun. 2015, 6.

High valent mononuclear iron-oxo species in catalytic O-O cleaving and forming reactions

251st National Meeting (2016)

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